Re: new module 'aligned-malloc'

[Jeffrey Walton]

On Wed, Jul 22, 2020 at 6:56 PM Bruno Haible <bruno@clisp.org> wrote:
>
> Hi Paul,
>
> > Of course this performance issue is mostly just for MS-Windows, as other 
> > major
> > current platforms already have aligned_alloc or rough equivalent.
>
> No, it's not only Windows. It's
>   - macOS
>   - Minix
>   - native Windows
>
> Here's the complete matrix:
>
>                      posix_memalign   aligned_alloc   memalign
>
> glibc                     Y                 Y             Y
> musl                      Y                 Y             Y
> macOS                     -                 -             -
> FreeBSD                   Y                 Y             -
> NetBSD                    Y                 -             -
> OpenBSD                   Y                 Y             -
> AIX                       Y                 -             -
> HP-UX                     -                 -             Y
> IRIX                      -                 -             Y
> Solaris 10                -                 -             Y
> Solaris 11                Y                 Y             -
> Minix                     -                 -             -
> Haiku                     Y                 -             Y
> Android                   Y                 -             Y
> Cygwin                    Y                 -             Y
> native Windows            -                 -             -

This may be helpful for OS X... all pointers returned from malloc(),
calloc() and friends are 16-byte aligned. From the OS X man page:

MALLOC(3)                BSD Library Functions Manual                MALLOC(3)

NAME
     calloc, free, malloc, realloc, reallocf, valloc -- memory allocation

SYNOPSIS
     #include <stdlib.h>

     void *
     calloc(size_t count, size_t size);

     void
     free(void *ptr);

     void *
     malloc(size_t size);

     void *
     realloc(void *ptr, size_t size);

     void *
     reallocf(void *ptr, size_t size);

     void *
     valloc(size_t size);

DESCRIPTION
     The malloc(), calloc(), valloc(), realloc(), and reallocf() functions
     allocate memory.  The allocated memory is aligned such that it can be
     used for any data type, including AltiVec- and SSE-related types.  The
     free() function frees allocations that were created via the preceding
     allocation functions.
     ...

Jeff